STA323W datasheet(47/71 Pages) STMICROELECTRONICS

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STA323W

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Channel 2 volume (address 0x09)

Channel 3 volume (address 0x0A)

7.8.3

Volume description

The volume structure of the STA323W consists of individual volume registers for each of the

three channels and a master volume register, and individual channel volume trim registers.

The channel volume settings are normally used to set the maximum allowable digital gain

and to hard-set gain differences between certain channels. These values are normally set at

the initialization of the IC and not changed. The individual channel volumes are adjustable in

0.5 dB steps from +48 dB to -80 dB. The master volume control is normally mapped to the

master volume of the system. The values of these two settings are summed to find the

actual gain or volume value for any given channel.

When set to 1, the Master Mute will mute all channels, whereas the individual channel

mutes (CxM) will mute only that channel. Both the Master Mute and the Channel Mutes

provide a “soft mute” with the volume ramping down to mute in 4096 samples from the

maximum volume setting at the internal processing rate (~96 kHz). A “hard mute” can be

obtained by setting a value of all 1’s (FFh) in any channel volume register or the master

volume register. When volume offsets are provided, via the master volume register, any

channel whose total volume is less than –100dB is muted.

All changes in volume take place at zero-crossings when ZCE = 1 (configuration register E)

on a per channel basis as this creates the smoothest possible volume transitions. When

ZCE=0, volume updates occur immediately.

The STA323W also features a soft-volume update function. When SVE = 1 (in configuration

feature can be disabled by setting SVE = 0.

Each channel also contains an individual channel volume bypass. If a particular channel has

volume bypassed via the CxVBP = 1 register then only the channel volume setting for that

particular channel affects the volume setting, the master volume setting does not affect that

channel. Also, master soft-mute does not affect the channel if CxVBP = 1.

Each channel also contains a channel mute. If CxM = 1 a soft mute is performed on that

channel.

C2V7

C2V6

C2V5

C2V4

C2V3

C2V2

C2V1

C2V0

110

000

C3V7

C3V6

C3V5

C3V4

C3V3

C3V2

C3V1

C3V0

110

000

STA323W 数据表(PDF) 47 Page - STMicroelectronics

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